[PATCH RFC 08/11] iommu: Handle IO page faults directly

[Lu Baolu <baolu.lu@linux.intel.com>]

Directly call the IO page fault handler in iommu_report_device_fault()
unless the device driver registered its own page fault handler. There
is no need to explicitly register the fault handler in IOMMU drivers.

Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
---
 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c | 13 +------------
 drivers/iommu/intel/iommu.c                     | 14 ++------------
 drivers/iommu/iommu.c                           | 11 ++++++++---
 3 files changed, 11 insertions(+), 27 deletions(-)

diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c
index 3537a2291d7c..8497425f3c13 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c
@@ -426,7 +426,6 @@ bool arm_smmu_master_sva_enabled(struct arm_smmu_master *master)
 
 static int arm_smmu_master_sva_enable_iopf(struct arm_smmu_master *master)
 {
-	int ret;
 	struct device *dev = master->dev;
 
 	/*
@@ -439,16 +438,7 @@ static int arm_smmu_master_sva_enable_iopf(struct arm_smmu_master *master)
 	if (!master->iopf_enabled)
 		return -EINVAL;
 
-	ret = iopf_queue_add_device(master->smmu->evtq.iopf, dev);
-	if (ret)
-		return ret;
-
-	ret = iommu_register_device_fault_handler(dev, iommu_queue_iopf, dev);
-	if (ret) {
-		iopf_queue_remove_device(master->smmu->evtq.iopf, dev);
-		return ret;
-	}
-	return 0;
+	return iopf_queue_add_device(master->smmu->evtq.iopf, dev);
 }
 
 static void arm_smmu_master_sva_disable_iopf(struct arm_smmu_master *master)
@@ -458,7 +448,6 @@ static void arm_smmu_master_sva_disable_iopf(struct arm_smmu_master *master)
 	if (!master->iopf_enabled)
 		return;
 
-	iommu_unregister_device_fault_handler(dev);
 	iopf_queue_remove_device(master->smmu->evtq.iopf, dev);
 }
 
diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
index 8781305b9a02..8f9cc66787c3 100644
--- a/drivers/iommu/intel/iommu.c
+++ b/drivers/iommu/intel/iommu.c
@@ -4760,7 +4760,6 @@ static int intel_iommu_enable_sva(struct device *dev)
 {
 	struct device_domain_info *info = dev_iommu_priv_get(dev);
 	struct intel_iommu *iommu;
-	int ret;
 
 	if (!info || dmar_disabled)
 		return -EINVAL;
@@ -4778,24 +4777,15 @@ static int intel_iommu_enable_sva(struct device *dev)
 	if (!info->pasid_enabled || !info->pri_enabled || !info->ats_enabled)
 		return -EINVAL;
 
-	ret = iopf_queue_add_device(iommu->iopf_queue, dev);
-	if (!ret)
-		ret = iommu_register_device_fault_handler(dev, iommu_queue_iopf, dev);
-
-	return ret;
+	return iopf_queue_add_device(iommu->iopf_queue, dev);
 }
 
 static int intel_iommu_disable_sva(struct device *dev)
 {
 	struct device_domain_info *info = dev_iommu_priv_get(dev);
 	struct intel_iommu *iommu = info->iommu;
-	int ret;
-
-	ret = iommu_unregister_device_fault_handler(dev);
-	if (!ret)
-		ret = iopf_queue_remove_device(iommu->iopf_queue, dev);
 
-	return ret;
+	return iopf_queue_remove_device(iommu->iopf_queue, dev);
 }
 
 static int intel_iommu_enable_iopf(struct device *dev)
diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index c0966fc9b686..4f90b71c6f6e 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -27,6 +27,8 @@
 #include <linux/cc_platform.h>
 #include <trace/events/iommu.h>
 
+#include "iommu-sva-lib.h"
+
 static struct kset *iommu_group_kset;
 static DEFINE_IDA(iommu_group_ida);
 
@@ -1177,10 +1179,9 @@ int iommu_report_device_fault(struct device *dev, struct iommu_fault_event *evt)
 	if (!param || !evt)
 		return -EINVAL;
 
-	/* we only report device fault if there is a handler registered */
 	mutex_lock(&param->lock);
 	fparam = param->fault_param;
-	if (!fparam || !fparam->handler) {
+	if (!fparam) {
 		ret = -EINVAL;
 		goto done_unlock;
 	}
@@ -1198,7 +1199,11 @@ int iommu_report_device_fault(struct device *dev, struct iommu_fault_event *evt)
 		mutex_unlock(&fparam->lock);
 	}
 
-	ret = fparam->handler(&evt->fault, fparam->data);
+	if (fparam->handler)
+		ret = fparam->handler(&evt->fault, fparam->data);
+	else
+		ret = iommu_queue_iopf(&evt->fault, fparam->data);
+
 	if (ret && evt_pending) {
 		mutex_lock(&fparam->lock);
 		list_del(&evt_pending->list);
-- 
2.25.1

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